Increased productivity and high out-of-seam dilution (15% to 20%) mining in US underground coal mines continue to generate dust control problems and the need to develop and implement alternate more efficient technologies for dust control. Additionally, several mines are facing reduced dust standards due to high respirable quartz content. Recent increasing trend in coal workers'pneumoconiosis has led Mine Safety and Health Administration (MSHA) and National Institute of Occupational Safety and Health (NIOSH) identifying coal mine dust as a high priority research area. Several mines in the Interior Coal Basin are having dust control problems and facing reduced respirable dust compliance standards because of: 1) High production rates, 2) About 15-20 % out-of-seam mining and 5-10% in-seam dilution, 3) Longer bolt holes for roof support, 4) Walk-through super-sections, 5) Inadequate characterization of silica/ quartz in the coal seam and immediate roof and floor strata, 6) Fineness of quartz dust generated and insufficient knowledge of its wetting characteristics, 7) Improper cutting sequence, and 8) Inadequate ventilation and dust control measures. Although the U.S. Bureau of Mines (USBM) and NIOSH have done extensive research on coal and quartz dusts, most of this research emphasized eastern U.S coal mines. Limited wettability studies of coal dust and quantification of respirable quartz at two mines (one in Illinois and one in Indiana) have indicated difficult to wet coal dusts in several areas and that immediate roof and floor strata have quartz content ranging from 25% to 35 % while the coal seam had quartz content varying from 2 % to 8%. These studies have identified a significant need for more systematic scientific studies on coal and quartz dusts characteristics in the region. The overall goals of this research are to: 1) Develop physical and chemical characteristics of different particle size coal and quartz/ silica dusts from different unit operations, 2) Utilize MSHA and company dust sampling data from the Interior Coal Basin mines to identify occupations and locations most exposed to coal and quartz and silica dust, 3) Develop surface and wettability characteristics for different size fractions of coal and silica dusts generated during mining, haulage and roof support operations, and 4) Identify engineering controls for respirable coal and silica dusts that would help the industry to meet MSHA standards immediately while longer-term measures are being developed. *Principal Investigator 1